Rounding/Transcript
Transcript Title text reads, The Mysteries of Life with Tim and Moby Tim & Moby are in a store. Tim puts several items down in front of the cashier: a kite, a video game, a bag of marbles, and a candy bar. A letter appears. Text reads as Tim narrates: Dear Tim and Moby, what does it mean to round a number? I'm curious. Thank you, Jeanette. TIM: When you round a number, you change it to a simpler one with roughly the same value. It’s basically an estimate. Moby beeps. TIM: No, you can't just choose any old number you want. There are some rules you have to follow. When you round something, first you have to decide what place value you want to round to. A label appears, reading, place value. TIM: A digit's place value is its position within a longer number. A number appears, reading: 454,345. TIM: For integers, or whole numbers, the lowest place value is the ones place, followed by the tens place, hundreds, thousands, and right on up. A label appears, reading, integers. Each digit of 454,345 is highlighted one at a time, starting from the right. Moby beeps. TIM: Take these marbles. On-screen, Tim picks up the bag of marbles. TIM: The package says each bag contains 17 of them. But say we wanted to round that number to the nearest 10. On-screen, 17 marbles appear. TIM: 17 is only three marbles away from 20. On-screen, three marbles are added to the original 17, making a total of 20 marbles. TIM: But it’s 7 away from 10. On-screen, seven marbles are taken away from the original 17, making a total of 10 marbles. TIM: So, 17 rounded to the nearest 10 is 20. Let’s try 14 marbles. On-screen, 14 marbles appear. TIM: 14 is closer to 10 than to 20, so we round it down to 10. On-screen, four marbles are taken away from the original 14, making a total of 10 marbles. Six marbles are added to the original 14, making a total of 20 marbles. Moby beeps. TIM: Right: if the number ends in 1 through 4, you round it down; if it ends in 5 through 9, round it up. This video game says it has 345 levels. On-screen, Tim picks up the video game. A number appears, reading, 345. TIM: To round to the nearest 10, look at the digit to the right of the tens place: it’s 5, which means you round up. On-screen, the digit: 5, in 345 is highlighted. The number rounds up from 345 to 350. TIM: So far so good. But what if you want to round it to the nearest 100? Same idea, but you’re gonna look at the digit to the right of the hundreds place instead. It’s a 4, so we round down. 345 rounded to the nearest hundred is 300. On-screen, the digit: 4, in 345 is highlighted. The number rounds down from 345 to 300. TIM: And you can do that for any number, no matter how big; just look at the digit to the right of the place value you’re rounding to. Moby beeps. TIM: Yeah, it’s the same for decimals, only you don’t put a 0 on the end. A label appears, reading, decimals. TIM: Like, say you want to round 3.45 to the nearest tenth. A number appears, reading, 3.45. TIM: You look at the digit to the right and round based on that. In this case, it’s 5, so we round up to 3.5, or 3 and five-tenths. On-screen, the digit, 5, in 3.45 is highlighted. The number rounds up from 3.45 to 3.50. TIM: But, because it’s a decimal, we don’t need to write the 0 on the end. On-screen, 3.50 becomes 3.5. Moby beeps. TIM: Well, rounding’s useful in a lot of real-life situations. Like now. I only have 50 dollars with me, but this kite costs 15 dollars and 33 cents, the candy bar costs 99 cents, the marbles cost 3 dollars and 75 cents, and the video game costs 29 99. On-screen, the items are listed with their prices. TIM: I could add up all those numbers, but I don’t have a calculator, and it’s kind of inconvenient to pull out a pencil and paper and write it all down in the middle of a store. So I’ll round the numbers. It’s a lot easier to add 15, 1, 4, and 30. On-screen, the prices are rounded to the nearest dollar. An equation reads: 15 plus 1 plus 4 plus 30 equals 50. TIM: That makes 50 dollars. Although that’s a little too close for comfort; let’s see what the exact price is. On-screen, the cashier rings up the items. The total comes to 50 dollars and 6 cents. TIM: Rats! See, that’s why it’s always a good idea to round up when you’re working with money. On-screen, the cashier adds tax to the total. It comes to 54 dollars and 44 cents. TIM: Double-rats! Uh, can I borrow 5 dollars? Moby taps Tim's forehead with his finger. TIM: Ow! What’d you do that for? Moby beeps. TIM: I do so know the value of a dollar! Category:BrainPOP Transcripts Category:BrainPOP Math Transcripts